2026 Allergy Season: What to Expect Across the U.S.
Pollen season is already underway in parts of the South and West, and according to a recent forecast from AccuWeather, the coming months will bring a mix of early starts, intense bursts, and regional variations depending on weather patterns.
Based on the analysis by AccuWeather meteorologist Brian Lada and Senior Meteorologist Alan Reppert, here is a summary of the 2026 allergy outlook—along with practical tips to manage exposure.
🌿 Key Factors That Influence Pollen Levels
As outlined by AccuWeather, several weather-related elements determine how severe the pollen season becomes:
| Factor | Effect |
|---|---|
| Temperature | Warmer ground temperatures help plants produce pollen more easily. |
| Rain | Heavy rain washes pollen from the air temporarily, but dry days afterward often cause sharp spikes. |
| Wind | Can carry pollen hundreds of miles, spreading allergens far from the source. |
| Frost | A late-spring frost may briefly suppress pollen, but often leads to a more intense rebound later in the season. |
🌳 Tree Pollen: Early Start in the South, Intense in the Ohio Valley
According to the AccuWeather forecast, tree pollen season has already begun across:
- Southern California
- Southern Arizona
- Much of the Gulf Coast
As temperatures rise, pollen levels will push northward through spring.
Hardest-Hit Regions
- Ohio Valley — Expected to experience periods of exceptionally high tree pollen, especially after spring rainfall.
- Pacific Northwest — Portland and Seattle may see an earlier-than-typical start with prolonged elevated levels.
- Plains — A slower start, but residents should prepare for a few days of extremely high counts before a quick drop-off.
- New England — Likely lower-than-average tree pollen due to a colder start and reduced rainfall.
“A later frost can help short-term pollen with lowering the tree pollen for a short time, but also increase pollen later in the season and make it more intense.”
— Alan Reppert, AccuWeather Senior Meteorologist
Reppert also noted that early-season trees like juniper and alder are hit harder by frost than late-season trees such as birch, maple, and pine.
🌾 Grass Pollen: Northern Spike, Mixed Outlook Elsewhere
Grass pollen typically rises as tree pollen fades. This year, AccuWeather predicts an early spike across the northern Plains and Great Lakes.
Areas to Watch
- Chicago, St. Louis, Minneapolis — Above-average rainfall combined with warmer weather is expected to drive much higher grass pollen levels.
- Texas — Above-average grass pollen for a few weeks, but a shorter season compared to northern areas.
- Gulf Coast — Near-normal rainfall and a drier summer start may keep grass pollen below average.
- Northwest — Hot, dry weather should suppress grass pollen, though any rainfall could trigger short-lived spikes.
“A combination of above-average rainfall and some warmer weather will bring much higher grass pollen levels.”
— Alan Reppert
🌾 Weed Pollen: Intense in the Rockies, Lower in Parts of the East
Weed pollen—including ragweed, thistle, sagebrush, and mugwort—peaks in late summer and early fall, ending with the first hard freeze.
Regional Breakdown
- Rockies — Higher rainfall and a longer warm period could lead to an intense weed pollen season, though it may end earlier than typical.
- Eastern Texas through Kentucky and Alabama — Cooler weather is expected to limit weed pollen levels.
- Coastal Oregon & Washington — Frequent storms provide moisture for weeds, but regular rainfall may wash pollen out before it builds up.
- Northeast — Lack of early rain and quickly dropping temperatures may keep pollen levels low, though any rain event could cause brief spikes.
✅ How to Reduce Allergy Exposure
AccuWeather’s forecast includes practical steps to help manage symptoms during peak pollen days:
- Limit outdoor time during early morning through early afternoon, when pollen production is highest.
- Change clothes and shower after spending time outside.
- Keep windows closed and use high-efficiency air filters.
- Start allergy medication before pollen levels surge, rather than waiting for symptoms to appear.
This summary is based on the original reporting by Brian Lada of AccuWeather, with analysis from Senior Meteorologist Alan Reppert. The full article, “2026 Allergy Forecast: When will pollen be bad across the US?,” was published March 4, 2026, and is available on the AccuWeather website. © 2026 AccuWeather, Inc.
